So I bought a 4 or so inch harlequin tusk - who is friendly - healthy and beautiful. He doesnt do any of the 'bad things' that they are supposed to do - he doesnt kill shrimp, snails, crabs, etc. However - he and his beautiful blue teeth when he expects to get fed - literally attack he will jump out of the water to try to grab food from my hand - often hitting my finger...... Advice??